#include <iostream>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

// ./tcpclient server-ip server-ip
int main(int argc,char* argv[])
{
    if(argc != 3)
    {
        std::cerr << "Usage: " << argv[0] << " server-ip server-port" << std::endl;
        exit(0);
    }
    std::string serverip = argv[1];
    uint16_t serverport = std::stoi(argv[2]);

    // 1.创建socket
    int sockfd = ::socket(AF_INET,SOCK_STREAM,0);
    if(sockfd < 0)
    {
        std::cerr << "create socket error" << std::endl;
        exit(1);
    }

    // 不需要显示的bind，但是一定要有自己的IP和port，需要隐式的绑定(OS用自己的IP和随机端口号)
    // 什么时候进行bind? If the connection or binding succeeds
    struct sockaddr_in server;
    memset(&server,0,sizeof(server));
    server.sin_family = AF_INET;
    server.sin_port = htons(serverport);
    // server.sin_addr.s_addr = 
    ::inet_pton(AF_INET,serverip.c_str(),&server.sin_addr);

    // 2.与服务端建立连接
    int n = ::connect(sockfd,(struct sockaddr*)&server,sizeof(server));
    // 也可以重连
    if(n < 0)
    {
        std::cerr << "connect socket error" << std::endl;
        exit(2);
    }

    // 3.发送消息
    while(true)
    {
        std::string message;
        std::cout << "Enter#";
        std::getline(std::cin,message);

        write(sockfd,message.c_str(),message.size());
        char echo_buffer[1024];
        n = read(sockfd,echo_buffer,sizeof(echo_buffer));
        if(n > 0)
        {
            echo_buffer[n] = 0;
            std::cout << echo_buffer << std::endl;
        }
        else
        {
            break;
        }
    }

    // 4.关闭socket
    ::close(sockfd);
    return 0;
}